Method and apparatus for releasing stuck drill pipe



Aug. 29, 1961 J. K. KERVER I 2,998,067

METHOD AND APPARATUS FOR RELEASING STUCK DRILL PIPE Filed July 22, 1957 DRILL PIPE JOHN K. KERVER, *PIPE GRIP BY ATTORNEY 2,998,067 METHOD AND APPARATUS FOR RELEASING STUCK DRILL PIPE John K. Kerver, Houston, Tex., assignor, by mesne assignments, to Jersey Production Research Company,

Tulsa, Okla, a corporation of Delaware Filed July 22, 1957, Ser. No. 673,187 8 Claims. '(Cl.16646) This invention concerns a method and apparatus for releasing pipe stuck in boreholes.

During drilling or other well operations pipe may become stuck or wedged in the borehole because of sedimentation, caving, etc. When oil or gas wells are drilled by the rotary method, the drill pipe occasionally becomes stuck in the borehole being drilled, because the drilled borehole tends to become slightly crooked. That is, when, during drilling, the direction of the borehole changes, a keyway or groove is worn or cut into the side of the borehole and when an attempt is made to pull or remove the drill pipe from the borehole thereafter, the drill pipe tends to straighten out and be forced tightly into the keyway. Drill collars or tool joints often hang in these grooves and become stuck.

When the stuck pipe cannot be pulled or otherwise released from its stuck position, it is necessary to out off the pipe and side track the borehole.

Briefly, the invention concerns a method for releasing well pipe, a portion of which is stuck in a borehole comprising applying an upwardly directed force to the pipe below the stuck portion. In one modification the invention provides for applying upwardly directed forces to the pipe above and below the stuck portion. In a second modification the invention provides for simultaneously applying to the pipe an upwardly directed force below the stuck portion and a downwardly directed force above the stuck portion.

The method of the invention utilizes apparatus for releasing the stuck well pipe comprising a first means secured to the pipe below the stuck portion adapted to apply an upwardly directed force to the pipe below the stuck portion, a second means secured to the pipe above the stuck portion adapted to apply an upwardly directed force to the pipe above the stuck portion and a third means secured to the pipe above the stuck portion adapted to apply a downwardly directed force to the pipe 'above the stuck portion.

The primary purpose of this invention is to provide an improved method and apparatus therefor for releasing pipe stuck or wedged in a borehole especially drill pipe which may become stuck during drilling operations.

This and other objects of the invention will be apparent from a description of the invention taken in conjunction with the drawings wherein:

FIG. 1 is a side elevation of the borehole and illustrates one manner of releasing and removing stuck pipe;

FIG. 2 is a side elevation, partly in section, of one type of apparatus adapted to secure a cable to a pipe;

FIG. 3 is a side elevation, partly in section, of another type apparatus adapted to secure a cable to a pipe;

FIG. 4 is a view taken on lines 4-4 of FIG. 3; and

FIG. 5 is a side elevation of a clamping means adapted to secure a cable to a pipe.

Referring more particularly to the drawings:

In FIG. 1 is shown a borehole in which is positioned a drill pipe or string 11. The direction of the borehole 10 has changed, as indicated at 12, forming thereby a keyway or groove 13 in which pipe 11 is wedged or stuck. A collar or tool joint 14 is shown lodged in keyway 13. A cable 15 is shown positioned within pipe 11 and extends from the upper end above the stuck portion of pipe 11 to below the stuck portion. A suitable pipe gripping means, indicated at 16, is shown arranged adjacent the lower end of pipe 11. An elevator 17 is shown connected to the upper end of the pipe 11. Elevator links 18 are connected to elevator 17 and extend to any suitable lifting means, such as a traveling block located on the drilling rig (not shown). The upper end of cable 15 also may be secured to the traveling block or may be secured to any other desirable lifting means.

In FIG. 2 is shown one type of pipe gripping apparatus for securing the cable 15 to the pipe 11 below the stuck portion. This apparatus comprises a tapered screw 20 secured to cable 15, as at 21. 'The tapered screw 20 is screw threadedly connected to expansion sections 22, which sections are provided with slips or wedge members 23. Upper and lower split rings 24 and 25, respectively, are arranged on expansion members 22. These rings are provided to urge expansible members 22 to retracted positions. Also drag springs 26 are arranged on expansion members 22, which springs: are adapted to center and to retard or prevent rotation of expansion members 22 in pipe 11. The operation of this apparatus is similar to the operation of a lag screw and expansion nut for bolting objects to concrete. Thus, rotation of cable 15 in one direction, as indicated by the arrowed directional line, causes tapered screw 20 to move downwardly within the expansible sections 22 thereby expanding sections 22 outwardly and moving slip members 23 into engagement with the inner wall of pipe 11. Slip members 23 may be released by rotating the cable 15 in a reverse direction.

Another embodiment of pipe gripping apparatus is shown in FIGS. 3 and 4. This embodiment utilizes a locking bar 30 secured to cable 15, as at 31. The pipe 11 is provided with a catch 32, which includes a shoulder 33 and a tapered surface 34. The catch 32 may be suitably permanently welded on the inside of pipe 11. The catch 32 is formed such that an opening 35 extends through the pipe 1 1 from above to below catch 32. In operation, locking bar 30 is lowered by means of cable 15 through opening 35 in catch 32. Cable 15 is then rotated a quarter turn '(or the pipe 11 may be rotated instead) and when an upward force is applied to cable 15, the upper surface of the locking bar 30 engages with shou-lder 33 of catch 32.

In FIG. 5 is shown a clamp for clamping cable 15 to the upper end of pipe 11. A tool joint box 40 is secured to pipe 11 and a split wireline clamp 41, provided with suitable bolt clamping means 42 and -a flange 43, engages the upper end of joint 40. Elevator 17 is secured to pipe =11 as in the embodiment of FIG. 1. The elevator links 18 extend to the traveling block (not shown) in order to provide a lifting force to pipe 11.

The operation is as follows:

As seen in FIG. 1, cable 15, with attached ,pipe igripping apparatus, such as illustrated in FIG. 2 or vFIGS. 3 and 4, is lowered through drill pipe 11 until the pipe gripping apparatus is positioned below the stuck portion of the pipe 11. Then the pipe gripping apparatus is engaged with the pipe and an upwardly directed force is applied to cable 15. Then, this lifting force on cable 15 may be released and an upwardly directed force applied to elevator 17. Thus, pipe 1 1 is lifted from the bottom and pulled from the top, alternately. Alternate pulling from the top and lifting from the bottom of pipe 11 tends to bend or bow the pipe and release it from the stuck position. In some instances it may be desirable to overlap the periods of pulling from above the stuck portion and lifting from below the stuck portion in which event the pulling and lifting operations will occur simultaneously at least part of the time. Beneficial action is ohtained by this method whether or not pipe 11 is stuck in a keyway, since if the pipe is stuck for other reasons, improved results are obtained because the portion of pipe 11 below the stuck portion is put in compression rather than in tension by the lifting force applied below the'stuck portion which thereby increases the eifective tensile strength of the pipe and in turn increases the resistance of the well pipe to shearing or breaking.

In the method according to another embodiment, cable is secured to pipe 11 below the stuck portion by means of apparatus such as illustrated in FIG. 2 or FIGS. 3 and 4 as in the previously described embodiment. Then a lifting force is exerted on cable 15 thereby applying an upwardly directed force to pipe 11 below the stuck port-ion. Then, the split wireline clamp 41 is moved into engagement with joint 40 and connected to the cable 15 by means of bolt clamping means 42 above the stuck portion of pipe llpwhile maintaining tension on cable 15. Thus, pipe 11 is placed in compression between the upper and lower cable connections. Upward force is then applied to the elevator links 18 thereby exerting a lifting force on pipe 11 to release the stuck pipe. By placing a portion of pipe 11 in compression a considerably greater pulling or lifting force can be applied to pipe 11 before the yield or breaking point of the pipe is exceeded because the tensile strength of the cable is added to the tensile strength of the well pipe, which increases the breaking or shearing point resistance of the well pipe. 7

The apparatus illustrated in FIGS. 2, 3, 4, and 5 are employed herein to illustrate the invention. Therefore, the invention is not to be considered as restricted to the specific type pipe gripping means and cable clamping means shown in these figures.

.While the invention has been described herein relative to the release and removal of a drill pipe stuck in a borehole, the invention is to be construed as encompassing release and removal of any pipe stuck in a well.

Having fully described the nature, operation, objects, and elements of my invention, I claim:

1. A method for releasing well pipe, a portion of which is stuck in a borehole comprising exerting from the earths surface an upwardly'directed force to said pipe applied at a location below said stuck portion, thereby placing in compression the well pipe between the stuck portion and the location of the application of said force; and exerting from the earths surface an upwardly directed force to said pipe applied at a location above said stuck portion whereby the effective tensile strength of said well pipe is increased.

2. A method as recited in claim 1 including exerting the forces applied below and above the stuck portion of said well pipe alternately.

' 3. A method as recited in claim 1 including over-. lapping exertion of the forces applied below and above the stuck portion of said Well pipe.

4. A method for releasing well pipe, a portion of which is stuck in a borehole comprising simultaneously exerting an upwardly directed force to said pipe applied at a location below said stuck portion and a downwardly directed force to said pipe applied at a location above said stock portion, thereby placing the well pipe in compression between the locations of the upwardly and downwardly directed forces; and exerting from the earths surface an upwardly directed force to said pipe applied at a location above said stuck portion whereby the effective tensile strength of the well pipe is increased.

'5. A method for releasing well pipe, a portion of which is stuck in a borehole comprising lowering pipe gripping means on a cable from the earths surface to below the stuck portion of said pipe; engaging said pipe gripping means with said pipe; attaching lifting means to said pipe above the stuck portion thereof; and then exerting an upwardly directed force applied to said pipe below the stuck portion by upwardly pulling said cable.

7 thereby placing in compression the well pipe between the stuck portion thereof and the location of the application of the force; and then exertin'g an upwardly directed force to said pipe above the stuck portion by upwardly pulling said lifting means whereby the effective tensile strength of the well pipe is increased.

6. A method as recited in claim 5 including upwardly pulling said cable and said lifting means alternately.

7. A method as recited in claim 5 including overlapping the periods of upwardly pulling said cable and said lifting means.

8. A method for releasing well pipe, a portion of which is stuck in a borehole comprising lowering pipe gripping means on a cable from the earths surface to below the stock portion of said pipe; engaging said pipe gripping means with said pipe; exerting an upwardly directed force applied to said pipe below the stuck portion by upwardly pulling said cable; attaching said cable to said pipe at a location above the stuck portion while maintaining tension on said cable, thereby placing said pipe in compression between the upper and lower cable connections to. said pipe;- attaching lifting means to said pipe at a location above the stuck portion thereof and then upwardly pulling said lifting means whereby the tensile strength of the cable is added to the tensile strength of the pipe to effectively increase the breaking resistance of said pipe.

, References Cited in the file of this patent V UNITED STATES PATENTS 7,841 

